<%= form_tag(Redsys::Tpv.tpv_url, id: 'redsys_tpv_form') do %>
  <%= hidden_field_tag 'Ds_SignatureVersion', Redsys::Tpv.signature_version %>
  <%= hidden_field_tag 'Ds_MerchantParameters', @tpv.merchant_params %>
  <%= hidden_field_tag 'Ds_Signature', @tpv.merchant_signature %>
<% end %>
<script type="text/javascript">
  document.getElementById("redsys_tpv_form").submit();
</script>